Watching the water supply

Why do we watch mountain snowpack so closely? Because mountain snow serves as a reservoir during spring and summer, gradually melting and feeding rivers and streams. Snow is an important part of our water supply. Let’s take a look at what’s going on as of Jan. 25, 2017:

Status of supplies

Weather and outlook | In December, we saw cooler-than-usual temperatures. Some parts of the state dipped to 20 degrees below average in the last two weeks. We haven’t seen too much precipitation statewide lately and we’re expected to stay relatively dry until the end of January.

We’re still experiencing La Nina conditions (cooler and wetter overall) but the forecast models see a high likelihood of switching into neutral conditions (neither La Nina nor El Nino) in the spring. While the models are currently sharing a slight consensus on warmer-than-normal temperatures for February through April, experts aren’t seeing indications of a sudden spring warmup like we had in 2016. That is good news for our snowpack.

Mountain snowpack | As of Jan. 25, our statewide mountain snowpack is 100 percent of average. The Olympic and lower Columbia regions are in the lead with 116 and 117 percent of normal, respectively. On the other end, the upper Yakima and Spokane regions are both at 76 percent of normal. Once this dry spell ends, experts believe we can expect our snowpack to continue building.

River and streams | Most rivers and streams on the west side of the state are running at near-normal or above-normal levels. Much of the east side is near normal, too, but there are some pockets of below-normal flows in parts of northeast and north central Washington. Colder areas are still seeing below-average flows because of ice.